On the natural polymorphism of pollen grains of Acer tataricum L.

To study natural polymorphism, pollen grains should be collected from ecologically clean sites. Taking the ecological conditions at the end of the 19th century and at the beginning of the 20th century as more favorable than the modern state, herbarium material (LE) was examined. In addition to typical (normally developed) pollen grains, we found two more morphological types within the range of natural polymorphism of pollen grains of Acer tataricum L. that were produced at the end of the 19th century and at the beginning of the 20th century.